gcc.dg/compat/struct-layout-1.exp does not supported installed-compiler testing

[Mark Mitchell]

DJ Delorie wrote:
>>(There's still a POSIX-ism in the generator, in that it tries to
>>write to "/dev/null".  On Windows systems, I bet this will often
>>work, but create a real file with that name.  It would be better,
>>and avoid portability problems, to guard the calls to fwrite, etc.,
>>with "if (file)" rather than spew to "/dev/null", but that's for
>>another day.)
> 
> 
> Both Cygwin and DJGPP know about /dev/null just fine.  I don't know
> about MinGW though.

It doesn't.  MinGW is just MSVCRT.

> But it's a lot faster if you don't do the write at all ;-)

Yes; that's why I said "better" in addition to "avoid portability 
problems". :-)

I kinda think any program opening /dev/null itself is slightly confused; 
/dev/null is a convenience for users to use with programs that insist on 
writing to a file, not for programs that might or might not themselves 
want to write to things.  Of course, this particular program is not 
performance-critical, so it's not like anyone has, or should have, tried 
hard to make it go maximally fast. :-)

-- 
Mark Mitchell
CodeSourcery, LLC
mark@codesourcery.com
(916) 791-8304